1. Field of the Invention
The invention relates generally to Micro-Electro-Mechanical Systems (MEMS). More particularly, the invention relates to a method for optimizing wafer bond line width for reduction of parasitic capacitance in MEMS accelerometers.
2. Description of Related Art
Micro-Electro-Mechanical Systems (MEMS) is the integration of mechanical elements, sensors, actuators, and electronics on a common silicon substrate through microfabrication technology. The electronics in a MEMS device are fabricated using Integrated Circuit (IC) technology (CMOS, Bipolar, or BICMOS processes), while the micromechanical components are fabricated using “micromachining” techniques that selectively etch away or add new layers to the silicon wafer to form mechanical and electromechanical devices.
MEMS devices are widely used in automotives, navigation systems, chemical and biological sensors, microoptics, accelerometers, pressure sensors and other devices. A common approach to fabrication of MEMS devices is the so-called bulk MEMS process. This process consists of processing two or three silicon wafers with patterns machined by Deep Reactive Ion Etching (DRIE) to form the structure used in each layer, and then bonding these layers together by a process called direct bonding to form a hermetic cavity.